The Hawaiian monk seal is a unique and endangered marine mammal. It is endemic to the Hawaiian Islands, found nowhere else in the world. This species holds a special place in Hawaii’s ecosystem, being one of only two mammals native to the islands. With a population of around 1,600 individuals, these seals are one of the most endangered seal species globally.
Northwestern Hawaiian Islands
The primary stronghold for the Hawaiian monk seal population is the remote Northwestern Hawaiian Islands (NWHI). Approximately 75% of the total monk seal population, around 1,200 individuals, resides in this chain of islands and atolls. These largely uninhabited islands provide expansive, undisturbed environments for their life cycle.
Within the NWHI, significant breeding subpopulations are found at locations such as Kure Atoll, Midway Islands, Pearl and Hermes Reef, Lisianski Island, Laysan Island, and French Frigate Shoals. Smaller groups also inhabit Necker Island and Nihoa Island. The isolation of these islands makes them important habitats for the species.
Main Hawaiian Islands
While historically concentrated in the NWHI, Hawaiian monk seals have shown an increasing presence in the Main Hawaiian Islands (MHI) in recent decades. This shift began around the 1990s, with a noticeable rise in sightings and births. The MHI population, though smaller, is growing and is increasingly important for the species’ recovery.
About 25% of the Hawaiian monk seal population, approximately 400 individuals, now lives among the Main Hawaiian Islands. These seals are commonly sighted on islands such as Kauai, Oahu, Maui, and Hawaii Island. The continued growth of this population, including more pups born in the MHI, is a positive trend for the species.
Factors Shaping Their Range
Hawaiian monk seals thrive in warm, subtropical waters, spending about two-thirds of their lives at sea. They forage in various marine environments, including shallow reefs, outer reef slopes, and submerged banks, seeking prey like fish, squid, octopus, and crustaceans near the seafloor. Some seals also utilize deeper water coral beds for hunting.
For resting, molting, and giving birth, these seals require terrestrial haul-out sites. They prefer sandy beaches, especially those protected and surrounded by shallow waters, for pupping. The availability of isolated and undisturbed environments is important for where these seals establish their habitats.
Safeguarding Their Homes
Conservation efforts are underway to protect the habitats of Hawaiian monk seals across their range. The Papahānaumokuākea Marine National Monument, which encompasses the Northwestern Hawaiian Islands, is a vast protected area. This monument provides a pristine environment for the majority of the monk seal population.
In the Main Hawaiian Islands, management strategies focus on reducing human-seal interactions and addressing habitat-related challenges. Efforts include community outreach to foster coexistence, responding to strandings, and relocating seals when necessary. Designated critical habitat areas, including beaches and surrounding marine waters, are important for supporting the species’ conservation.